A typical dielectric resonator device used in a transmitter-receiver apparatus, such as a communication apparatus and a radar apparatus, is provided with a circuit substrate having a ground electrode and a transmission line, and a dielectric resonator which is attached to the circuit substrate at a position facing the ground electrode so as to be coupled to the transmission line (for example, see Patent Document 1).
Patent Document 1: Japanese Unexamined Patent Application Publication No. 11-214908
In such prior art, the dielectric resonator is defined by a TE010-mode resonator that has, for example, electrodes disposed on opposite surfaces of a dielectric substrate, and these electrodes are respectively provided with circular openings that face each other. The electrodes of the TE010-mode resonator are electrically connected to the ground electrode of the circuit substrate, such that the electrodes of the TE010-mode resonator are supported by the ground electrode.
In the prior art, the electrodes of the TE010-mode resonator are electrically connected to the ground electrode of the circuit substrate with, for example, a conductive projection. For this reason, if a bump, for example, is used as the conductive projection, a designated device or process is necessary for the attachment of the bump. This leads to an increase in manufacturing costs. Furthermore, since an inexpensive insulative resin material is used for the circuit substrate while a high dielectric ceramic substrate is used for the TE010-mode resonator, a thermal stress may be generated between the circuit substrate and the TE010-mode resonator due to a difference in coefficient of linear expansion between the two. This may possibly cause a disengagement of the joined section between the ground electrode of the circuit substrate and the electrodes of the TE010-mode resonator. The disengagement of the joined section induces a change in a current path, thus easily leading to fluctuation of the characteristics of the TE010-mode resonator.